Refers to a compound of formula (i) wherein R1 is a group piridilo or pirimidinilo and D is Cyclopentyl, Cyclohexyl, tetrahidrofuranilo, among others. Preferred compounds are 1 - tetrahydropyran - 6 - (4 - (2 - pyrimidin-2-yl) - cyclobutyl} - 1.5 - dihydro - pyrazolo [3,4-d] pyrimidine - 4 - One 1 - (4 - difluoro cyclohexyl) - 6 - (4 - (2 - pyridin) cyclobutyl} - dihydro - - 1.5 pyrazolo [3,4-d] pyrimidine - 4 - ona, among others.It also relates to a Pharmaceutical composition comprising such PDE9 show inhibitory Properties and are useful for the treatment of conditions related to impairments in the perception or Memory, Concentration, LearningREFERIDO A UN COMPUESTO DE FORMULA (I) DONDE R1 ES UN GRUPO PIRIDILO O PIRIMIDINILO Y D ES CICLOPENTILO, CICLOHEXILO, TETRAHIDROFURANILO, ENTRE OTROS. SON COMPUESTOS PREFERIDOS 1- TETRAHIDROPIRANO-6-{4-(2-PIRIMIDIN)-CICLOBUTIL}-1,5-DIHIDRO-PIRAZOLO [3,4-D] PIRIMIDIN-4-ONA 1-(4-DIFLUORO CICLOHEXIL)-6-{4-(2-PIRIDIN)-CICLOBUTIL}-1,5-DIHIDRO-PIRAZOLO [3,4-D] PIRIMIDIN-4-ONA, ENTRE OTROS. SE REFIERE TAMBIEN A UNA COMPOSICION FARMACEUTICA, DICHOS COMPUESTO MUESTRAN PROPIEDADES INHIBIDORAS DE LA PDE9 Y SON UTILES PARA EL TRATAMIENTO DE AFECCIONES RELACIONADAS CON DEFICIENCIAS EN LA PERCEPCION, CONCENTRACION, APRENDIZAJE O MEMORIA
